Thermal insulating rings (application of ceramic fiber)

This product was developed as a high temperature thermal insulation such as in diffusion furnace and CVD equipment used in semiconductor manufacturing processes.
Used for semiconductor manufacturing equipment, diffusion furnace and other high temperature insulation materials.


  • ・This ring can be produced to match the shape of the quartz tube and silicon carbide tube loaded in the furnace.
  • ・Compared to silica wool and silica insulation, this material has high thermal resistance, excellent sealing characteristics and does not react with the quartz tube.
  • ・Since alumina fiber is used, it features longer service life than silica fiber enabling reduction of insulation replacement frequency and wastes generated.
  • ・Customers can select between low impurity and normal types as requested.
    ※The low impurity type uses low impurity materials in the outer materials, inner filler and sewing thread.
  • ・Thermal insulating rings have thermal resistance of 1200℃.
  • ・We recommend reed-shaped filler with to avoid particle generation in locations that had been filled with silica wool.
  • ・To prevent smoke issues after installation, all products are provided after baking.

Materials composition of Thermal Insulating Ring

low impurities type general type
outer materials Almax B cloth HG-3025-T
Almax B cloth HG-4018-D (thick)
Almax B cloth 3025-T
Almax B cloth 4018-D (thick)
inner filler Ceramics fiber blanket
Ceramics fiber board
Ceramics fiber board (hardened type)
Ceramics fiber blanket
Ceramics fiber board
Ceramics fiber board (hardened type)
sweing thread Almax B HG-T-5760D Almax B T-5760D
binding string Almax B sleeve HG-SV-4 Almax B sleeve SV-4

Almax B (ceramic fiber)

Appropriate for use in fields of cutting edge technology such as fuel cell batteries due to its thermal resistance and insulation.
We have 5 kinds of shapes available.

Almax B (low impurities) Almax B
crystal phase δ-Alumina δ-Alumina
chemical composition Al2O3 72% 72%
SiO2 28% 28%
fiber diameter (μm) 7 7
bulk density (g/cm3) 2.9 2.9
thermal resistance (℃) 1200 1200
features low-impurity high mechanical strength/good machinability
minor component (ppm) Fe 258 630
Na 18 1100
Ca <1 180
P <2 <100
Cu 4 65
K <1 100
  • yarn,
  • cloth,
  • sleeve,
  • tape and felt (Almax B only)

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